FreeBSD/Linux Kernel Cross Reference
sys/amd64/amd64/trap.c
1 /*-
2 * Copyright (C) 1994, David Greenman
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * the University of Utah, and William Jolitz.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. All advertising materials mentioning features or use of this software
18 * must display the following acknowledgement:
19 * This product includes software developed by the University of
20 * California, Berkeley and its contributors.
21 * 4. Neither the name of the University nor the names of its contributors
22 * may be used to endorse or promote products derived from this software
23 * without specific prior written permission.
24 *
25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
35 * SUCH DAMAGE.
36 *
37 * from: @(#)trap.c 7.4 (Berkeley) 5/13/91
38 */
39
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD: releng/10.3/sys/amd64/amd64/trap.c 294136 2016-01-16 07:56:49Z dchagin $");
42
43 /*
44 * AMD64 Trap and System call handling
45 */
46
47 #include "opt_clock.h"
48 #include "opt_cpu.h"
49 #include "opt_hwpmc_hooks.h"
50 #include "opt_isa.h"
51 #include "opt_kdb.h"
52 #include "opt_kdtrace.h"
53
54 #include <sys/param.h>
55 #include <sys/bus.h>
56 #include <sys/systm.h>
57 #include <sys/proc.h>
58 #include <sys/pioctl.h>
59 #include <sys/ptrace.h>
60 #include <sys/kdb.h>
61 #include <sys/kernel.h>
62 #include <sys/ktr.h>
63 #include <sys/lock.h>
64 #include <sys/mutex.h>
65 #include <sys/resourcevar.h>
66 #include <sys/signalvar.h>
67 #include <sys/syscall.h>
68 #include <sys/sysctl.h>
69 #include <sys/sysent.h>
70 #include <sys/uio.h>
71 #include <sys/vmmeter.h>
72 #ifdef HWPMC_HOOKS
73 #include <sys/pmckern.h>
74 PMC_SOFT_DEFINE( , , page_fault, all);
75 PMC_SOFT_DEFINE( , , page_fault, read);
76 PMC_SOFT_DEFINE( , , page_fault, write);
77 #endif
78
79 #include <vm/vm.h>
80 #include <vm/vm_param.h>
81 #include <vm/pmap.h>
82 #include <vm/vm_kern.h>
83 #include <vm/vm_map.h>
84 #include <vm/vm_page.h>
85 #include <vm/vm_extern.h>
86
87 #include <machine/cpu.h>
88 #include <machine/intr_machdep.h>
89 #include <x86/mca.h>
90 #include <machine/md_var.h>
91 #include <machine/pcb.h>
92 #ifdef SMP
93 #include <machine/smp.h>
94 #endif
95 #include <machine/tss.h>
96
97 #ifdef KDTRACE_HOOKS
98 #include <sys/dtrace_bsd.h>
99 #endif
100
101 extern void trap(struct trapframe *frame);
102 extern void syscall(struct trapframe *frame);
103 void dblfault_handler(struct trapframe *frame);
104
105 static int trap_pfault(struct trapframe *, int);
106 static void trap_fatal(struct trapframe *, vm_offset_t);
107
108 #define MAX_TRAP_MSG 32
109 static char *trap_msg[] = {
110 "", /* 0 unused */
111 "privileged instruction fault", /* 1 T_PRIVINFLT */
112 "", /* 2 unused */
113 "breakpoint instruction fault", /* 3 T_BPTFLT */
114 "", /* 4 unused */
115 "", /* 5 unused */
116 "arithmetic trap", /* 6 T_ARITHTRAP */
117 "", /* 7 unused */
118 "", /* 8 unused */
119 "general protection fault", /* 9 T_PROTFLT */
120 "trace trap", /* 10 T_TRCTRAP */
121 "", /* 11 unused */
122 "page fault", /* 12 T_PAGEFLT */
123 "", /* 13 unused */
124 "alignment fault", /* 14 T_ALIGNFLT */
125 "", /* 15 unused */
126 "", /* 16 unused */
127 "", /* 17 unused */
128 "integer divide fault", /* 18 T_DIVIDE */
129 "non-maskable interrupt trap", /* 19 T_NMI */
130 "overflow trap", /* 20 T_OFLOW */
131 "FPU bounds check fault", /* 21 T_BOUND */
132 "FPU device not available", /* 22 T_DNA */
133 "double fault", /* 23 T_DOUBLEFLT */
134 "FPU operand fetch fault", /* 24 T_FPOPFLT */
135 "invalid TSS fault", /* 25 T_TSSFLT */
136 "segment not present fault", /* 26 T_SEGNPFLT */
137 "stack fault", /* 27 T_STKFLT */
138 "machine check trap", /* 28 T_MCHK */
139 "SIMD floating-point exception", /* 29 T_XMMFLT */
140 "reserved (unknown) fault", /* 30 T_RESERVED */
141 "", /* 31 unused (reserved) */
142 "DTrace pid return trap", /* 32 T_DTRACE_RET */
143 };
144
145 #ifdef KDB
146 static int kdb_on_nmi = 1;
147 SYSCTL_INT(_machdep, OID_AUTO, kdb_on_nmi, CTLFLAG_RW,
148 &kdb_on_nmi, 0, "Go to KDB on NMI");
149 TUNABLE_INT("machdep.kdb_on_nmi", &kdb_on_nmi);
150 #endif
151 static int panic_on_nmi = 1;
152 SYSCTL_INT(_machdep, OID_AUTO, panic_on_nmi, CTLFLAG_RW,
153 &panic_on_nmi, 0, "Panic on NMI");
154 TUNABLE_INT("machdep.panic_on_nmi", &panic_on_nmi);
155 static int prot_fault_translation;
156 SYSCTL_INT(_machdep, OID_AUTO, prot_fault_translation, CTLFLAG_RW,
157 &prot_fault_translation, 0,
158 "Select signal to deliver on protection fault");
159 static int uprintf_signal;
160 SYSCTL_INT(_machdep, OID_AUTO, uprintf_signal, CTLFLAG_RW,
161 &uprintf_signal, 0,
162 "Print debugging information on trap signal to ctty");
163
164 /*
165 * Exception, fault, and trap interface to the FreeBSD kernel.
166 * This common code is called from assembly language IDT gate entry
167 * routines that prepare a suitable stack frame, and restore this
168 * frame after the exception has been processed.
169 */
170
171 void
172 trap(struct trapframe *frame)
173 {
174 #ifdef KDTRACE_HOOKS
175 struct reg regs;
176 #endif
177 struct thread *td = curthread;
178 struct proc *p = td->td_proc;
179 int i = 0, ucode = 0, code;
180 u_int type;
181 register_t addr = 0;
182 ksiginfo_t ksi;
183
184 PCPU_INC(cnt.v_trap);
185 type = frame->tf_trapno;
186
187 #ifdef SMP
188 /* Handler for NMI IPIs used for stopping CPUs. */
189 if (type == T_NMI) {
190 if (ipi_nmi_handler() == 0)
191 goto out;
192 }
193 #endif /* SMP */
194
195 #ifdef KDB
196 if (kdb_active) {
197 kdb_reenter();
198 goto out;
199 }
200 #endif
201
202 if (type == T_RESERVED) {
203 trap_fatal(frame, 0);
204 goto out;
205 }
206
207 #ifdef HWPMC_HOOKS
208 /*
209 * CPU PMCs interrupt using an NMI. If the PMC module is
210 * active, pass the 'rip' value to the PMC module's interrupt
211 * handler. A return value of '1' from the handler means that
212 * the NMI was handled by it and we can return immediately.
213 */
214 if (type == T_NMI && pmc_intr &&
215 (*pmc_intr)(PCPU_GET(cpuid), frame))
216 goto out;
217 #endif
218
219 if (type == T_MCHK) {
220 mca_intr();
221 goto out;
222 }
223
224 #ifdef KDTRACE_HOOKS
225 /*
226 * A trap can occur while DTrace executes a probe. Before
227 * executing the probe, DTrace blocks re-scheduling and sets
228 * a flag in its per-cpu flags to indicate that it doesn't
229 * want to fault. On returning from the probe, the no-fault
230 * flag is cleared and finally re-scheduling is enabled.
231 */
232 if (dtrace_trap_func != NULL && (*dtrace_trap_func)(frame, type))
233 goto out;
234 #endif
235
236 if ((frame->tf_rflags & PSL_I) == 0) {
237 /*
238 * Buggy application or kernel code has disabled
239 * interrupts and then trapped. Enabling interrupts
240 * now is wrong, but it is better than running with
241 * interrupts disabled until they are accidentally
242 * enabled later.
243 */
244 if (ISPL(frame->tf_cs) == SEL_UPL)
245 uprintf(
246 "pid %ld (%s): trap %d with interrupts disabled\n",
247 (long)curproc->p_pid, curthread->td_name, type);
248 else if (type != T_NMI && type != T_BPTFLT &&
249 type != T_TRCTRAP) {
250 /*
251 * XXX not quite right, since this may be for a
252 * multiple fault in user mode.
253 */
254 printf("kernel trap %d with interrupts disabled\n",
255 type);
256
257 /*
258 * We shouldn't enable interrupts while holding a
259 * spin lock.
260 */
261 if (td->td_md.md_spinlock_count == 0)
262 enable_intr();
263 }
264 }
265
266 code = frame->tf_err;
267
268 if (ISPL(frame->tf_cs) == SEL_UPL) {
269 /* user trap */
270
271 td->td_pticks = 0;
272 td->td_frame = frame;
273 addr = frame->tf_rip;
274 if (td->td_ucred != p->p_ucred)
275 cred_update_thread(td);
276
277 switch (type) {
278 case T_PRIVINFLT: /* privileged instruction fault */
279 i = SIGILL;
280 ucode = ILL_PRVOPC;
281 break;
282
283 case T_BPTFLT: /* bpt instruction fault */
284 case T_TRCTRAP: /* trace trap */
285 enable_intr();
286 #ifdef KDTRACE_HOOKS
287 if (type == T_BPTFLT) {
288 fill_frame_regs(frame, ®s);
289 if (dtrace_pid_probe_ptr != NULL &&
290 dtrace_pid_probe_ptr(®s) == 0)
291 goto out;
292 }
293 #endif
294 frame->tf_rflags &= ~PSL_T;
295 i = SIGTRAP;
296 ucode = (type == T_TRCTRAP ? TRAP_TRACE : TRAP_BRKPT);
297 break;
298
299 case T_ARITHTRAP: /* arithmetic trap */
300 ucode = fputrap_x87();
301 if (ucode == -1)
302 goto userout;
303 i = SIGFPE;
304 break;
305
306 case T_PROTFLT: /* general protection fault */
307 i = SIGBUS;
308 ucode = BUS_OBJERR;
309 break;
310 case T_STKFLT: /* stack fault */
311 case T_SEGNPFLT: /* segment not present fault */
312 i = SIGBUS;
313 ucode = BUS_ADRERR;
314 break;
315 case T_TSSFLT: /* invalid TSS fault */
316 i = SIGBUS;
317 ucode = BUS_OBJERR;
318 break;
319 case T_ALIGNFLT:
320 i = SIGBUS;
321 ucode = BUS_ADRALN;
322 break;
323 case T_DOUBLEFLT: /* double fault */
324 default:
325 i = SIGBUS;
326 ucode = BUS_OBJERR;
327 break;
328
329 case T_PAGEFLT: /* page fault */
330 /*
331 * Emulator can take care about this trap?
332 */
333 if (*p->p_sysent->sv_trap != NULL &&
334 (*p->p_sysent->sv_trap)(td) == 0)
335 goto userout;
336
337 addr = frame->tf_addr;
338 i = trap_pfault(frame, TRUE);
339 if (i == -1)
340 goto userout;
341 if (i == 0)
342 goto user;
343
344 if (i == SIGSEGV)
345 ucode = SEGV_MAPERR;
346 else {
347 if (prot_fault_translation == 0) {
348 /*
349 * Autodetect.
350 * This check also covers the images
351 * without the ABI-tag ELF note.
352 */
353 if (SV_CURPROC_ABI() == SV_ABI_FREEBSD
354 && p->p_osrel >= P_OSREL_SIGSEGV) {
355 i = SIGSEGV;
356 ucode = SEGV_ACCERR;
357 } else {
358 i = SIGBUS;
359 ucode = BUS_PAGE_FAULT;
360 }
361 } else if (prot_fault_translation == 1) {
362 /*
363 * Always compat mode.
364 */
365 i = SIGBUS;
366 ucode = BUS_PAGE_FAULT;
367 } else {
368 /*
369 * Always SIGSEGV mode.
370 */
371 i = SIGSEGV;
372 ucode = SEGV_ACCERR;
373 }
374 }
375 break;
376
377 case T_DIVIDE: /* integer divide fault */
378 ucode = FPE_INTDIV;
379 i = SIGFPE;
380 break;
381
382 #ifdef DEV_ISA
383 case T_NMI:
384 /* machine/parity/power fail/"kitchen sink" faults */
385 if (isa_nmi(code) == 0) {
386 #ifdef KDB
387 /*
388 * NMI can be hooked up to a pushbutton
389 * for debugging.
390 */
391 if (kdb_on_nmi) {
392 printf ("NMI ... going to debugger\n");
393 kdb_trap(type, 0, frame);
394 }
395 #endif /* KDB */
396 goto userout;
397 } else if (panic_on_nmi)
398 panic("NMI indicates hardware failure");
399 break;
400 #endif /* DEV_ISA */
401
402 case T_OFLOW: /* integer overflow fault */
403 ucode = FPE_INTOVF;
404 i = SIGFPE;
405 break;
406
407 case T_BOUND: /* bounds check fault */
408 ucode = FPE_FLTSUB;
409 i = SIGFPE;
410 break;
411
412 case T_DNA:
413 /* transparent fault (due to context switch "late") */
414 KASSERT(PCB_USER_FPU(td->td_pcb),
415 ("kernel FPU ctx has leaked"));
416 fpudna();
417 goto userout;
418
419 case T_FPOPFLT: /* FPU operand fetch fault */
420 ucode = ILL_COPROC;
421 i = SIGILL;
422 break;
423
424 case T_XMMFLT: /* SIMD floating-point exception */
425 ucode = fputrap_sse();
426 if (ucode == -1)
427 goto userout;
428 i = SIGFPE;
429 break;
430 #ifdef KDTRACE_HOOKS
431 case T_DTRACE_RET:
432 enable_intr();
433 fill_frame_regs(frame, ®s);
434 if (dtrace_return_probe_ptr != NULL &&
435 dtrace_return_probe_ptr(®s) == 0)
436 goto out;
437 break;
438 #endif
439 }
440 } else {
441 /* kernel trap */
442
443 KASSERT(cold || td->td_ucred != NULL,
444 ("kernel trap doesn't have ucred"));
445 switch (type) {
446 case T_PAGEFLT: /* page fault */
447 (void) trap_pfault(frame, FALSE);
448 goto out;
449
450 case T_DNA:
451 KASSERT(!PCB_USER_FPU(td->td_pcb),
452 ("Unregistered use of FPU in kernel"));
453 fpudna();
454 goto out;
455
456 case T_ARITHTRAP: /* arithmetic trap */
457 case T_XMMFLT: /* SIMD floating-point exception */
458 case T_FPOPFLT: /* FPU operand fetch fault */
459 /*
460 * For now, supporting kernel handler
461 * registration for FPU traps is overkill.
462 */
463 trap_fatal(frame, 0);
464 goto out;
465
466 case T_STKFLT: /* stack fault */
467 case T_PROTFLT: /* general protection fault */
468 case T_SEGNPFLT: /* segment not present fault */
469 if (td->td_intr_nesting_level != 0)
470 break;
471
472 /*
473 * Invalid segment selectors and out of bounds
474 * %rip's and %rsp's can be set up in user mode.
475 * This causes a fault in kernel mode when the
476 * kernel tries to return to user mode. We want
477 * to get this fault so that we can fix the
478 * problem here and not have to check all the
479 * selectors and pointers when the user changes
480 * them.
481 */
482 if (frame->tf_rip == (long)doreti_iret) {
483 frame->tf_rip = (long)doreti_iret_fault;
484 goto out;
485 }
486 if (frame->tf_rip == (long)ld_ds) {
487 frame->tf_rip = (long)ds_load_fault;
488 goto out;
489 }
490 if (frame->tf_rip == (long)ld_es) {
491 frame->tf_rip = (long)es_load_fault;
492 goto out;
493 }
494 if (frame->tf_rip == (long)ld_fs) {
495 frame->tf_rip = (long)fs_load_fault;
496 goto out;
497 }
498 if (frame->tf_rip == (long)ld_gs) {
499 frame->tf_rip = (long)gs_load_fault;
500 goto out;
501 }
502 if (frame->tf_rip == (long)ld_gsbase) {
503 frame->tf_rip = (long)gsbase_load_fault;
504 goto out;
505 }
506 if (frame->tf_rip == (long)ld_fsbase) {
507 frame->tf_rip = (long)fsbase_load_fault;
508 goto out;
509 }
510 if (curpcb->pcb_onfault != NULL) {
511 frame->tf_rip = (long)curpcb->pcb_onfault;
512 goto out;
513 }
514 break;
515
516 case T_TSSFLT:
517 /*
518 * PSL_NT can be set in user mode and isn't cleared
519 * automatically when the kernel is entered. This
520 * causes a TSS fault when the kernel attempts to
521 * `iret' because the TSS link is uninitialized. We
522 * want to get this fault so that we can fix the
523 * problem here and not every time the kernel is
524 * entered.
525 */
526 if (frame->tf_rflags & PSL_NT) {
527 frame->tf_rflags &= ~PSL_NT;
528 goto out;
529 }
530 break;
531
532 case T_TRCTRAP: /* trace trap */
533 /*
534 * Ignore debug register trace traps due to
535 * accesses in the user's address space, which
536 * can happen under several conditions such as
537 * if a user sets a watchpoint on a buffer and
538 * then passes that buffer to a system call.
539 * We still want to get TRCTRAPS for addresses
540 * in kernel space because that is useful when
541 * debugging the kernel.
542 */
543 if (user_dbreg_trap()) {
544 /*
545 * Reset breakpoint bits because the
546 * processor doesn't
547 */
548 /* XXX check upper bits here */
549 load_dr6(rdr6() & 0xfffffff0);
550 goto out;
551 }
552 /*
553 * FALLTHROUGH (TRCTRAP kernel mode, kernel address)
554 */
555 case T_BPTFLT:
556 /*
557 * If KDB is enabled, let it handle the debugger trap.
558 * Otherwise, debugger traps "can't happen".
559 */
560 #ifdef KDB
561 if (kdb_trap(type, 0, frame))
562 goto out;
563 #endif
564 break;
565
566 #ifdef DEV_ISA
567 case T_NMI:
568 /* machine/parity/power fail/"kitchen sink" faults */
569 if (isa_nmi(code) == 0) {
570 #ifdef KDB
571 /*
572 * NMI can be hooked up to a pushbutton
573 * for debugging.
574 */
575 if (kdb_on_nmi) {
576 printf ("NMI ... going to debugger\n");
577 kdb_trap(type, 0, frame);
578 }
579 #endif /* KDB */
580 goto out;
581 } else if (panic_on_nmi == 0)
582 goto out;
583 /* FALLTHROUGH */
584 #endif /* DEV_ISA */
585 }
586
587 trap_fatal(frame, 0);
588 goto out;
589 }
590
591 /* Translate fault for emulators (e.g. Linux) */
592 if (*p->p_sysent->sv_transtrap)
593 i = (*p->p_sysent->sv_transtrap)(i, type);
594
595 ksiginfo_init_trap(&ksi);
596 ksi.ksi_signo = i;
597 ksi.ksi_code = ucode;
598 ksi.ksi_trapno = type;
599 ksi.ksi_addr = (void *)addr;
600 if (uprintf_signal) {
601 uprintf("pid %d comm %s: signal %d err %lx code %d type %d "
602 "addr 0x%lx rsp 0x%lx rip 0x%lx "
603 "<%02x %02x %02x %02x %02x %02x %02x %02x>\n",
604 p->p_pid, p->p_comm, i, frame->tf_err, ucode, type, addr,
605 frame->tf_rsp, frame->tf_rip,
606 fubyte((void *)(frame->tf_rip + 0)),
607 fubyte((void *)(frame->tf_rip + 1)),
608 fubyte((void *)(frame->tf_rip + 2)),
609 fubyte((void *)(frame->tf_rip + 3)),
610 fubyte((void *)(frame->tf_rip + 4)),
611 fubyte((void *)(frame->tf_rip + 5)),
612 fubyte((void *)(frame->tf_rip + 6)),
613 fubyte((void *)(frame->tf_rip + 7)));
614 }
615 KASSERT((read_rflags() & PSL_I) != 0, ("interrupts disabled"));
616 trapsignal(td, &ksi);
617
618 user:
619 userret(td, frame);
620 KASSERT(PCB_USER_FPU(td->td_pcb),
621 ("Return from trap with kernel FPU ctx leaked"));
622 userout:
623 out:
624 return;
625 }
626
627 static int
628 trap_pfault(frame, usermode)
629 struct trapframe *frame;
630 int usermode;
631 {
632 vm_offset_t va;
633 struct vmspace *vm;
634 vm_map_t map;
635 int rv = 0;
636 vm_prot_t ftype;
637 struct thread *td = curthread;
638 struct proc *p = td->td_proc;
639 vm_offset_t eva = frame->tf_addr;
640
641 if (__predict_false((td->td_pflags & TDP_NOFAULTING) != 0)) {
642 /*
643 * Due to both processor errata and lazy TLB invalidation when
644 * access restrictions are removed from virtual pages, memory
645 * accesses that are allowed by the physical mapping layer may
646 * nonetheless cause one spurious page fault per virtual page.
647 * When the thread is executing a "no faulting" section that
648 * is bracketed by vm_fault_{disable,enable}_pagefaults(),
649 * every page fault is treated as a spurious page fault,
650 * unless it accesses the same virtual address as the most
651 * recent page fault within the same "no faulting" section.
652 */
653 if (td->td_md.md_spurflt_addr != eva ||
654 (td->td_pflags & TDP_RESETSPUR) != 0) {
655 /*
656 * Do nothing to the TLB. A stale TLB entry is
657 * flushed automatically by a page fault.
658 */
659 td->td_md.md_spurflt_addr = eva;
660 td->td_pflags &= ~TDP_RESETSPUR;
661 return (0);
662 }
663 } else {
664 /*
665 * If we get a page fault while in a critical section, then
666 * it is most likely a fatal kernel page fault. The kernel
667 * is already going to panic trying to get a sleep lock to
668 * do the VM lookup, so just consider it a fatal trap so the
669 * kernel can print out a useful trap message and even get
670 * to the debugger.
671 *
672 * If we get a page fault while holding a non-sleepable
673 * lock, then it is most likely a fatal kernel page fault.
674 * If WITNESS is enabled, then it's going to whine about
675 * bogus LORs with various VM locks, so just skip to the
676 * fatal trap handling directly.
677 */
678 if (td->td_critnest != 0 ||
679 WITNESS_CHECK(WARN_SLEEPOK | WARN_GIANTOK, NULL,
680 "Kernel page fault") != 0) {
681 trap_fatal(frame, eva);
682 return (-1);
683 }
684 }
685 va = trunc_page(eva);
686 if (va >= VM_MIN_KERNEL_ADDRESS) {
687 /*
688 * Don't allow user-mode faults in kernel address space.
689 */
690 if (usermode)
691 goto nogo;
692
693 map = kernel_map;
694 } else {
695 /*
696 * This is a fault on non-kernel virtual memory. If either
697 * p or p->p_vmspace is NULL, then the fault is fatal.
698 */
699 if (p == NULL || (vm = p->p_vmspace) == NULL)
700 goto nogo;
701
702 map = &vm->vm_map;
703
704 /*
705 * When accessing a usermode address, kernel must be
706 * ready to accept the page fault, and provide a
707 * handling routine. Since accessing the address
708 * without the handler is a bug, do not try to handle
709 * it normally, and panic immediately.
710 */
711 if (!usermode && (td->td_intr_nesting_level != 0 ||
712 curpcb->pcb_onfault == NULL)) {
713 trap_fatal(frame, eva);
714 return (-1);
715 }
716 }
717
718 /*
719 * If the trap was caused by errant bits in the PTE then panic.
720 */
721 if (frame->tf_err & PGEX_RSV) {
722 trap_fatal(frame, eva);
723 return (-1);
724 }
725
726 /*
727 * PGEX_I is defined only if the execute disable bit capability is
728 * supported and enabled.
729 */
730 if (frame->tf_err & PGEX_W)
731 ftype = VM_PROT_WRITE;
732 else if ((frame->tf_err & PGEX_I) && pg_nx != 0)
733 ftype = VM_PROT_EXECUTE;
734 else
735 ftype = VM_PROT_READ;
736
737 if (map != kernel_map) {
738 /*
739 * Keep swapout from messing with us during this
740 * critical time.
741 */
742 PROC_LOCK(p);
743 ++p->p_lock;
744 PROC_UNLOCK(p);
745
746 /* Fault in the user page: */
747 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
748
749 PROC_LOCK(p);
750 --p->p_lock;
751 PROC_UNLOCK(p);
752 } else {
753 /*
754 * Don't have to worry about process locking or stacks in the
755 * kernel.
756 */
757 rv = vm_fault(map, va, ftype, VM_FAULT_NORMAL);
758 }
759 if (rv == KERN_SUCCESS) {
760 #ifdef HWPMC_HOOKS
761 if (ftype == VM_PROT_READ || ftype == VM_PROT_WRITE) {
762 PMC_SOFT_CALL_TF( , , page_fault, all, frame);
763 if (ftype == VM_PROT_READ)
764 PMC_SOFT_CALL_TF( , , page_fault, read,
765 frame);
766 else
767 PMC_SOFT_CALL_TF( , , page_fault, write,
768 frame);
769 }
770 #endif
771 return (0);
772 }
773 nogo:
774 if (!usermode) {
775 if (td->td_intr_nesting_level == 0 &&
776 curpcb->pcb_onfault != NULL) {
777 frame->tf_rip = (long)curpcb->pcb_onfault;
778 return (0);
779 }
780 trap_fatal(frame, eva);
781 return (-1);
782 }
783 return ((rv == KERN_PROTECTION_FAILURE) ? SIGBUS : SIGSEGV);
784 }
785
786 static void
787 trap_fatal(frame, eva)
788 struct trapframe *frame;
789 vm_offset_t eva;
790 {
791 int code, ss;
792 u_int type;
793 long esp;
794 struct soft_segment_descriptor softseg;
795 char *msg;
796
797 code = frame->tf_err;
798 type = frame->tf_trapno;
799 sdtossd(&gdt[NGDT * PCPU_GET(cpuid) + IDXSEL(frame->tf_cs & 0xffff)],
800 &softseg);
801
802 if (type <= MAX_TRAP_MSG)
803 msg = trap_msg[type];
804 else
805 msg = "UNKNOWN";
806 printf("\n\nFatal trap %d: %s while in %s mode\n", type, msg,
807 ISPL(frame->tf_cs) == SEL_UPL ? "user" : "kernel");
808 #ifdef SMP
809 /* two separate prints in case of a trap on an unmapped page */
810 printf("cpuid = %d; ", PCPU_GET(cpuid));
811 printf("apic id = %02x\n", PCPU_GET(apic_id));
812 #endif
813 if (type == T_PAGEFLT) {
814 printf("fault virtual address = 0x%lx\n", eva);
815 printf("fault code = %s %s %s%s, %s\n",
816 code & PGEX_U ? "user" : "supervisor",
817 code & PGEX_W ? "write" : "read",
818 code & PGEX_I ? "instruction" : "data",
819 code & PGEX_RSV ? " rsv" : "",
820 code & PGEX_P ? "protection violation" : "page not present");
821 }
822 printf("instruction pointer = 0x%lx:0x%lx\n",
823 frame->tf_cs & 0xffff, frame->tf_rip);
824 if (ISPL(frame->tf_cs) == SEL_UPL) {
825 ss = frame->tf_ss & 0xffff;
826 esp = frame->tf_rsp;
827 } else {
828 ss = GSEL(GDATA_SEL, SEL_KPL);
829 esp = (long)&frame->tf_rsp;
830 }
831 printf("stack pointer = 0x%x:0x%lx\n", ss, esp);
832 printf("frame pointer = 0x%x:0x%lx\n", ss, frame->tf_rbp);
833 printf("code segment = base 0x%lx, limit 0x%lx, type 0x%x\n",
834 softseg.ssd_base, softseg.ssd_limit, softseg.ssd_type);
835 printf(" = DPL %d, pres %d, long %d, def32 %d, gran %d\n",
836 softseg.ssd_dpl, softseg.ssd_p, softseg.ssd_long, softseg.ssd_def32,
837 softseg.ssd_gran);
838 printf("processor eflags = ");
839 if (frame->tf_rflags & PSL_T)
840 printf("trace trap, ");
841 if (frame->tf_rflags & PSL_I)
842 printf("interrupt enabled, ");
843 if (frame->tf_rflags & PSL_NT)
844 printf("nested task, ");
845 if (frame->tf_rflags & PSL_RF)
846 printf("resume, ");
847 printf("IOPL = %ld\n", (frame->tf_rflags & PSL_IOPL) >> 12);
848 printf("current process = %d (%s)\n",
849 curproc->p_pid, curthread->td_name);
850
851 #ifdef KDB
852 if (debugger_on_panic || kdb_active)
853 if (kdb_trap(type, 0, frame))
854 return;
855 #endif
856 printf("trap number = %d\n", type);
857 if (type <= MAX_TRAP_MSG)
858 panic("%s", trap_msg[type]);
859 else
860 panic("unknown/reserved trap");
861 }
862
863 /*
864 * Double fault handler. Called when a fault occurs while writing
865 * a frame for a trap/exception onto the stack. This usually occurs
866 * when the stack overflows (such is the case with infinite recursion,
867 * for example).
868 */
869 void
870 dblfault_handler(struct trapframe *frame)
871 {
872 #ifdef KDTRACE_HOOKS
873 if (dtrace_doubletrap_func != NULL)
874 (*dtrace_doubletrap_func)();
875 #endif
876 printf("\nFatal double fault\n");
877 printf("rip = 0x%lx\n", frame->tf_rip);
878 printf("rsp = 0x%lx\n", frame->tf_rsp);
879 printf("rbp = 0x%lx\n", frame->tf_rbp);
880 #ifdef SMP
881 /* two separate prints in case of a trap on an unmapped page */
882 printf("cpuid = %d; ", PCPU_GET(cpuid));
883 printf("apic id = %02x\n", PCPU_GET(apic_id));
884 #endif
885 panic("double fault");
886 }
887
888 int
889 cpu_fetch_syscall_args(struct thread *td, struct syscall_args *sa)
890 {
891 struct proc *p;
892 struct trapframe *frame;
893 register_t *argp;
894 caddr_t params;
895 int reg, regcnt, error;
896
897 p = td->td_proc;
898 frame = td->td_frame;
899 reg = 0;
900 regcnt = 6;
901
902 params = (caddr_t)frame->tf_rsp + sizeof(register_t);
903 sa->code = frame->tf_rax;
904
905 if (sa->code == SYS_syscall || sa->code == SYS___syscall) {
906 sa->code = frame->tf_rdi;
907 reg++;
908 regcnt--;
909 }
910 if (p->p_sysent->sv_mask)
911 sa->code &= p->p_sysent->sv_mask;
912
913 if (sa->code >= p->p_sysent->sv_size)
914 sa->callp = &p->p_sysent->sv_table[0];
915 else
916 sa->callp = &p->p_sysent->sv_table[sa->code];
917
918 sa->narg = sa->callp->sy_narg;
919 KASSERT(sa->narg <= sizeof(sa->args) / sizeof(sa->args[0]),
920 ("Too many syscall arguments!"));
921 error = 0;
922 argp = &frame->tf_rdi;
923 argp += reg;
924 bcopy(argp, sa->args, sizeof(sa->args[0]) * regcnt);
925 if (sa->narg > regcnt) {
926 KASSERT(params != NULL, ("copyin args with no params!"));
927 error = copyin(params, &sa->args[regcnt],
928 (sa->narg - regcnt) * sizeof(sa->args[0]));
929 }
930
931 if (error == 0) {
932 td->td_retval[0] = 0;
933 td->td_retval[1] = frame->tf_rdx;
934 }
935
936 return (error);
937 }
938
939 #include "../../kern/subr_syscall.c"
940
941 /*
942 * System call handler for native binaries. The trap frame is already
943 * set up by the assembler trampoline and a pointer to it is saved in
944 * td_frame.
945 */
946 void
947 amd64_syscall(struct thread *td, int traced)
948 {
949 struct syscall_args sa;
950 int error;
951 ksiginfo_t ksi;
952
953 #ifdef DIAGNOSTIC
954 if (ISPL(td->td_frame->tf_cs) != SEL_UPL) {
955 panic("syscall");
956 /* NOT REACHED */
957 }
958 #endif
959 error = syscallenter(td, &sa);
960
961 /*
962 * Traced syscall.
963 */
964 if (__predict_false(traced)) {
965 td->td_frame->tf_rflags &= ~PSL_T;
966 ksiginfo_init_trap(&ksi);
967 ksi.ksi_signo = SIGTRAP;
968 ksi.ksi_code = TRAP_TRACE;
969 ksi.ksi_addr = (void *)td->td_frame->tf_rip;
970 trapsignal(td, &ksi);
971 }
972
973 KASSERT(PCB_USER_FPU(td->td_pcb),
974 ("System call %s returing with kernel FPU ctx leaked",
975 syscallname(td->td_proc, sa.code)));
976 KASSERT(td->td_pcb->pcb_save == get_pcb_user_save_td(td),
977 ("System call %s returning with mangled pcb_save",
978 syscallname(td->td_proc, sa.code)));
979
980 syscallret(td, error, &sa);
981
982 /*
983 * If the user-supplied value of %rip is not a canonical
984 * address, then some CPUs will trigger a ring 0 #GP during
985 * the sysret instruction. However, the fault handler would
986 * execute in ring 0 with the user's %gs and %rsp which would
987 * not be safe. Instead, use the full return path which
988 * catches the problem safely.
989 */
990 if (td->td_frame->tf_rip >= VM_MAXUSER_ADDRESS)
991 set_pcb_flags(td->td_pcb, PCB_FULL_IRET);
992 }
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